| Environnement, ingénierie & développement |  |
N°7 - 3ème Trimestre 1997
1. Éditorial n°7 Déchets Sciences et Techniques
Notre civilisation qui a vu l'apparition de risques jusqu'ici inconnus (énergie nucléaire, biotechnologies, transport aérien ... ) est souvent décrite comme une civilisation du risque. Elle n'en est pas moins une civilisation de la sécurité, même s'il est surprenant de constater que la demande sociale conduit à un niveau d'exigence très élevé à l'égard des dispositifs techniques ou collectifs, alors que les choix de vie personnelle n'ont pas amélioré la sécurité individuelle, voire l'ont aggravé (tabagisme, conduite automobile, sports extrêmes ... ).Le principe de précaution auquel est consacré un ouvrage récent [Oliver Godard : Le principe de précaution dans la conduite des affaires humaines. Éditions de la Maison des Sciences de l'Homme, Paris, 1997] en est une illustration. Ce principe repose sur l'idée qu'il peut être justifié, voire impératif de limiter, encadrer ou empêcher certaines activités potentiellement dangereuses, sans attendre qu'un lien de causalité soit scientifiquement établi. Il s'agit là d'une notion ambivalente. Fallait-il, par exemple, au nom de ce principe, interdire le développement du chemin de fer au siècle dernier sous prétexte qu'il pouvait avoir des conséquences dangereuses pour la population ? Pour autant faut-il accepter toute innovation technologique simplement parce qu'elle est innovante ?
2. Déchet et imaginaire: Le paradigme du corps étranger toxique
Cette étude qualitative analyse, à travers les représentations individuelles et collectives du déchet et de la décharge, l'imaginaire associé à des objets. Ces associations éclairent les résistances à l'information et la dynamique de rejet, d'opposition que suscitent les projets d'implantation d'installation de traitement des déchets. Le dégagement des significations imaginaires du déchet-décharge suppose l'accès et le recours à l'action. Elle seule permet de ne plus se vivre comme exposé à la charge mortifère du déchet, de restaurer une position à la fois de sujet et d'acteur.
3. Recherches concertées avec les industriels en matière d'environnement: Exemple du réseau coopératif de recherche sur les déchets (RE.CO.R.D.)
During the month of December 1989 the RECORD (co-operative network on waste research) Association aw initiated by the French Ministry of Environment, answering by this way the requests to HSMRC (Hazardous Substance Management Research Center) an other American co-operative network located in NJIT (New Jersey lnstitute of Technology). The complexity of problems that are arisen by waste management and the load of investments necessary for a more fundamental approach of solutions justify by themselves to resort to a co-operative action. RECORD thus appears as the result of a threefold cooperation: that of manufactures who are wishful to summon up their purposes and their research capabilities, that of public authorities (ADEME – Energy improvement and control agency - and Ministry of Environment) and that of research workers whose activities nearly cover the totality of the fields physico, chemistry, mechanics, biology, economy, sociology, and so on.
4. Les contraintes financières pour les collectivités locales françaises dans la gestion des déchets
Waste precollection, collection and treatment is more and more expensive. As the quality of collection and treatment get better, its cost is increasing. ln 2002, according to the objectives of the law, a local authority will attain 20% to 25% of recycling, 20% of composting and 55% to 65% of incineration with energy recovery. The operation cost will be around 1.300 FF/ waste ton including TVA: 220 FF.
5. Environnement et technico-économie des procédés industriels: Partie 1 : la nuisance des produits
The interactions of any industrial process with its environment, are located either upstream due to the rarity of natural resources, or downstream due to the rejection of noxious by-products. The nuisance intensity is defined for each polluting agent. A simple method for calculating the total nuisance of any industrial product is defined, as the sum of the nuisances produced by each process of the product manufacture. As an example, the inventory of the air, water and rejected solids pollutions during the production of one kilogram of steel is presented.
6. Les techniques de traitement physique des matières premières minérales appliquées aux déchets: La séparation inox austénitique – graphite de déchets de l’industrie nucléaire
The BRGM group applies its know-how, inherited from mineral processing, to waste treatment and environment. As an application in association with Framatome the build up of a grinding and magnetic separation processfor a stainless/graphite waste from nuclear industry is presented. After a set-up at pilot scale this process is used at industrial scale on a contamined medium. This example shows the interest of using mechanical preparation and magnetic sorting techniques to separate wastes components.
7. Connaissance et valorisation des composts par la procédure de qualification agronomique
Composting is a suitable treatment for the organic fraction of waste and provides an end-product to agriculture. However, as a consequence of the lack of informations, the environmental impact of composting is difficult to assess. Furthermore, the agronomic properties of a compost from urban waste are barely studied. This article proposes a procedure to assess all types of compost from waste. This procedure sets up the agronomic properties of compost as well as their environmental impact (in term of threshold). lt comprises two steps:- in laboratory, a set of tests to measure the agronomic effectiveness and the innocuousness towards vegetals;- on field, in situ tests to confirm the first results. This procedure has been implemented on 6 types of compost which represent the actual situation of composting in France: compost from MSW, compost of MSW after the separative collection of packaging, compost from biowaste, compost from green waste an sludge, compost from sludge and MSW. This procedure can be implemented on mature compost, before land application.
8. L'électromigration appliquée à la dépollution des sols: Le cas d'une pollution fluorée
The aim of this study is to scale up the electrokinetic process. A methodology was then developed, in order to implement the adapted conditions for the fluorine polluted soil decontamination, by using an electromigration process. First, a laboratory experimental study was carried out in order to analyse the influence of different parameters (electrolyte type, soil granulometry, applied electrical potential). Then other studies have been performed, using three scales (0.8, 20 and 1500 litres) to observe the impact of the scale up on the removed fluorine amount, treatment time and the energy consumption parameters.
9. Apports potentiels de la théorie des possibilités à l’évaluation des risques environnementaux
Some environmental problems, such as the impact of a contaminated site, are characterized by the initial paucity of reliable data, and the uncertainty about acceptance criteria for released pollutants. It is shown how the « theory of possibility », particularly the concepts of fuzzy numbers and of necessity measure, can be used to assess the acceptability of such situations. This theory is advocated to supply an acceptable implementation scheme for the « principle of precaution », by avoiding overconservative assumptions. These rather new tools would deserve improved communication mainly toward regulators and decision-makers.